TM-9-2320-361-24-1 Field Maintenance Manual Volume 1 for M44A2 Series Trucks
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TM 9-2320-361-24-1 0010 00 0010 00-20 COMPRESSED AIR AND BRAKE SYSTEM TROUBLESHOOTING (Contd) Table 4. Air-Operated Troubleshooting Procedures (Contd). MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 2. FRONT WHEEL DRIVE DOES NOT ENGAGE (FRONT WHEEL DRIVE LOCK- IN SWITCH ENGAGED) 1. Start engine (TM 9-2320-361-10) and allow air pressure to build up to normal operating pressure. 2. Inspect lines and hoses for air leaks. Test 1. Check front axle engagement air cylinder supply line (1) pressure. 1. Stop engine and open all drain valves (TM 9-2320-361-10) until brake system air is completely drained. 2. Disconnect supply line (1) from air cylinder elbow (3). 3. Remove elbow (3) from air cylinder (2). 4. Install tee (5) on air cylinder (2). 5. Connect test gauge (4) and supply line (1) to tee (5). 6. Start engine (TM 9-2320-361- 10) and allow air pressure to build up to normal operating pressure. 7. Place front wheel drive lock-in switch in ON position. NOTE Air pressure gauge on instrument panel has a maximum pressure reading of 120 psi. If old governor has been replaced with new governor, air pressure may exceed maximum pressure reading on instrument panel gauge reading. 8. Check reading on test gauge (4) and compare reading to instrument panel air pressure gauge. 9. Check air cylinder on transfer for leaks. 1. If air leaks are found, repair or replace as required (TM 9-243). 2. If no leaks are found, perform test 1. 1. If reading is zero, replace front wheel drive lock-in switch (WP 0135 00). 2. If test gauge (4) reading is lower than instrument panel gauge reading, and air can be heard escaping from transfer case vent, replace PTO (WP 0348 00). If air leaks are found, replace air cylinder (WP 0136 00).